The purpose of the mutagenesis core is to provide assistance to each of the research projects in the administration of mutagens and the subsequent follow-up and observation of the animals until they are assayed. The mutagens to be used in commin are ENU and 4-aminobiphenyl. DMBA will be used by Drs. Tishfield and Doetschman, and ionizing radiation by Drs. Stringer and Tishfield. The Cobalt-60 source, however, is not part of the mutagenesis core, but is available through Dr. Denman, a radiation biologist, in Radiology (see attached letter). The core also will provide adduct analysis, particularly for Dr. Doetschman's project.